SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bdcc4c364dbc6eac3460ff53a62045cd7ec5a5a0b144080d43d00d4760fc3c6' 
  AND token = 'lsBADvwo/bIoxycin2GXdAeKVkfyY3NHqeXMVwvtaO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}