SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '26b2bba75135ca84794733e50ed1493bdccb6c81bf42d963f4b2389cf6be8443' 
  AND token = 'CRgc8vAsCwmYf5VAYynA3Xx7QI3vbw7asF1RzCMKU1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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