SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7592ec46799235d322caa05148a2c630166f3e0087cb23eff8b0259d0bdb786d' 
  AND token = 'JTuUVVgW9hOH292UC/GWkHkZwWpDcQF6XfsuqOiYhs0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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