SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48e8487c4e8aade61a7755ad5e264c5e276158dd8145fd910f0832d959e64353' 
  AND token = 'ElcjgvvRhFXQrFDjh1EkwaM9tUApjOX1nm7ehNDSCIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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