SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c52f99cef74efc931d2152fd543da529be6690d29b6d99c02db73735c0030f58' 
  AND token = '4Iq9n8fZ9lHVYnj/FGlJ8sEvRPuDpOVBk7L1xFTC3WU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}