SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'edc66fdb0026d3bb6024ed85f5f599407def3d09fc0f0e80fac7ec5860518220' 
  AND token = 'zGwYOPL04zmNDTbl5bmuf7ZM+dLxhCHCXxct2AtIpAc=' 
  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"
    }
  }
}