SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '862770533b28a617f212a48f593e0a532ec29237eba9840546fb8bb05b3082e8' 
  AND token = 'teR8QplQXLLBMdOFrNQOFynI3Vm/YcBh6uGJjzr/C4E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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