SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1582cfdbd281b55a608fdfd66fe987da9466cd5441853c39c24042df55144b72' 
  AND token = 'hKzdOR6HFL3Pz/ynkBhvVz8f3wFSRYPThcGrN5cvye0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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