SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'baa86175ba128d143b0ded1e964b025574186d08012a369584e1cdfabdda447a' 
  AND token = 'L/ycZngKJcpqXRmoDTCJ78XY0UNR+oTcnLaC7lDaEVY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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