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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '189ebb59f4b7bdb468d9df6f0b1433786435d42a78ff9c38e3b18f7a2fe1951a' 
  AND token = 'Mj57bAF0X8MGFgtDpWvusgTKnq2uygLD3u6oqd0zQ6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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