SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bac43eac70b222b2665663e89c7cb6ae0a0bf349bfb51916d3256f1bebd413b' 
  AND token = 'nhju9HZMxFrsndUcnDmUggDZl3Lj0sMwB7rB0SUfKus=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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