SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9fd59331e7a7e3209488d92a533724270edf9822ae34bf0f7a8a072894a9921' 
  AND token = 'mLanvSeeM4oJTrhvL0wIn99un0hJklWMU92pkpDonSM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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