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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bd38a7a3cbc8f8b385810cc2c03ec054afa1f70b12b7ef427d15ca6128a1add' 
  AND token = 'Ya8jbsNVw8zmIdtB0xuCT36pjYcYoIbt9gyC9IHSXfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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