SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62d9cefb67b40491d23f7fa5d82ba7763c38a23c472ec885cb7cf52456888c38' 
  AND token = 'g03gYvER7VMckaluzsVCWdalTkYGy+NbElHObIk1+cs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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