SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9e32209a734f3353f8935f40174c613c80594df7f5a731613db2b451a6941ded' 
  AND token = 'OqGqe5/KdAwv2hLJcCPPkjtRTwuMfimngF8yKUbiGeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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