SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a714e1a31628bb49af2f4ee0e721700569ed3da4c5f2b6eba90728e2e4342d2' 
  AND token = 'jrCkSWKTdXxUuzpAslpu3RdtoKfr18suv0AHC2rwCk0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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