SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '91af83ce0344ddb30e3ecac20ecc762235a71a66a8ae7a9ded6e951125236ba6' 
  AND token = 'FgL7Tykte7/grNGYmMP1hGhXu6fhRqo5SkCA7S7TBww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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