SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b15105f2f1a8774893a0485880159b2cc79995ab1a041a5ce135831ab121e90' 
  AND token = 'nllDHzowyvgcAx5w/BCvmZhsuopUOtHmOTp27d45lDA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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